Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board BSA A65 5 speed gearboxes

Earlier today I visited NOVA Racing Transmissions to show them an A65 crankcase and gearbox parts.

There were mentioned earlier and are worth a look: - http://novaracing.co.uk/ManufacturerBSA.html

The guys are going to look at the design and manufacture of a ‘modern’ 5 speed gearbox that can be accommodated within the existing crankcases. This would involve a much more reliable barrel selector rather than the quadrant currently used.

There are some serious issues with the Quaife box as far as I can see. 1 – 1st gear is too tall. 2 – the jump from 4th to 5th is too great. 3 – the selector fork arrangement has to potential to be unreliable.

The good news is that unlike Quaife, they won’t require an initial batch of 25 off but just 5! However the price is likely to be quite high but the benefits are that the ‘box will be designed by a team of experts who are dedicated motorcycle gear manufacturers who have successfully designed many gearboxes that not only work but also win races!

As soon as I have any further information of ratios and prices I will happily post them here.

In the meantime – expressions of interest please?

Thanks

I think a barrel selector would have to be rather small diameter to fit. There is about 0.625" from the centre of the existing fork shaft to the gearbox shell and the first gear is already very close to the fork shaft. The barrel selector is definitely a better design but fitting without surgery might be a problem.

Hi Dave, this and other issues are exactly why I left NOVA with the crankcases and other gear parts. Martin seemed optimistic that he could find a solution and I will post the result as soon as I hear from them.

I like the cassette structure. The std camplate system works nicely. I welded and modified the tracks a little on my 4speed so the gears all get full engagement in the dogs. I know if the shimming or engagement of the dogs is not right they can wear on the dogs and jump out of gear, but the actual system works and it can be very slick shifting. I'm sure a 5speed could work with the same system.

Hi

I have 5 x 5-speed boxes for the A65 which should be ready by the end of November. As this isn't my post, I'll do a new post next week with the details, once I get home.

John

Nick, do you think people would want to shell out extra for a splined clutch hub? I am building a new clutch using KTM plates and either could be accomodated. I have never had a hardened key split so I am not aware of it being a problem.

Nick I'm sure my A65 box shifts as well as the T150V I once had, both being good. I just use it like a jap gearbox and use the clutch mostly only on down shifts, the exception on upshifts is if I cannot give it at least a little throttle to put load on before shifting. A good operating clutch also makes a big difference to the feel of the box, as does the gear stick or linkage. I used to use a very extended reversed lever, with a long travel, now I use a linkage system with less travel and it's nice.

I had a quick conversation with NOVA this morning and the design team has confirmed that this is NOT a problem DM.

As soon as I have further details I will post here as I understand that sufficient design work has now been done to be able to firm up on the main technical attributes.

Thanks DoubleDiamond, Nova shipped me my gearset.

I have fitted the Nova 5 speed box to my A65 and combined with the Newby clutch and my home grown rear set kit,this is now different bike,tried and tested on the Moto Piston rally in Spain last September,can’t wait for the better British weather. I Wish !
Ken

Having 5speeds is definitely a lovely thing.

https://www.youtube.com/watch?v=a_FSM22SokU